Add a convenience method to copy wrapping, exact, and fast-math flags (NFC).

The loop vectorizer preserves wrapping, exact, and fast-math properties of scalar instructions.
This patch adds a convenience method to make that operation easier because we need to do this
in the loop vectorizer, SLP vectorizer, and possibly other places.

Although this is a 'no functional change' patch, I've added a testcase to verify that the exact
flag is preserved by the loop vectorizer. The wrapping and fast-math flags are already checked
in existing testcases.

Differential Revision: http://reviews.llvm.org/D5138

llvm-svn: 216886

1 files changed, 3 insertions, 13 deletions

diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 5ca9106e652..ba330128788 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -3248,19 +3248,9 @@ void InnerLoopVectorizer::vectorizeBlockInLoop(BasicBlock *BB, PhiVector *PV) {
       for (unsigned Part = 0; Part < UF; ++Part) {
         Value *V = Builder.CreateBinOp(BinOp->getOpcode(), A[Part], B[Part]);
 
-        // Update the NSW, NUW and Exact flags. Notice: V can be an Undef.
-        BinaryOperator *VecOp = dyn_cast<BinaryOperator>(V);
-        if (VecOp && isa<OverflowingBinaryOperator>(BinOp)) {
-          VecOp->setHasNoSignedWrap(BinOp->hasNoSignedWrap());
-          VecOp->setHasNoUnsignedWrap(BinOp->hasNoUnsignedWrap());
-        }
-        if (VecOp && isa<PossiblyExactOperator>(VecOp))
-          VecOp->setIsExact(BinOp->isExact());
-
-        // Copy the fast-math flags.
-        if (VecOp && isa<FPMathOperator>(V))
-          VecOp->setFastMathFlags(it->getFastMathFlags());
-
+        if (BinaryOperator *VecOp = dyn_cast<BinaryOperator>(V))
+          VecOp->copyFlags(BinOp);
+        
         Entry[Part] = V;
       }